Flexible electroencephalography headset

ABSTRACT

One variation of a system for locating electrodes on a head of a user includes a headset defining a set of electrode bodies elastically interconnected by a unique set of spring elements configured to locate the set of electrode bodies at electrode positions of the international 10-20 standard, irrespective of the size of the head of the user. The spring elements are configured to carry electrical signals between interconnected electrode bodies and ultimately to a controller. An electrode tip is mechanically and electrically coupled to each electrode body. The electrode tip comprises a thin conductive probe mounted at the distal end of an elastic beam and is configured to extend from a base of the electrode tip, bypass hair, and electrically couple to the head of the user, and an insulative boss, configured to rest on and transfer the weight of the headset to the head of the user.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of U.S. Provisional Application No.63/229,871, filed on 5 Aug. 2021, and U.S. Provisional Application No.63/256,238, filed on 15 Oct. 2021, both of which are incorporated intheir entireties by this reference.

This Application is related to U.S. patent application Ser. No.15/351,016, filed on 14 Nov. 2016 which is incorporated in its entiretyby this reference.

TECHNICAL FIELD

This invention relates generally to the field of electro-encephalopathyand more specifically to a new and useful method for collectingelectrical measurements in the field of electro-encephalopathy.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of a system;

FIGS. 2A-2C are schematic diagrams of one variation of the system; and

FIGS. 3A-3B are schematic diagrams of one variation of the system.

DESCRIPTION OF THE EMBODIMENTS

The following description of embodiments of the invention is notintended to limit the invention to these embodiments but rather toenable a person skilled in the art to make and use this invention.Variations, configurations, implementations, example implementations,and examples described herein are optional and are not exclusive to thevariations, configurations, implementations, example implementations,and examples they describe. The invention described herein can includeany and all permutations of these variations, configurations,implementations, example implementations, and examples.

1. System

Generally, a system 100 for locating electrodes on a head of a userincludes a set of electrode bodies configured to locate at electrodepositions of an electroencephalography (or “EEG”) standard, such as theinternational 10-20 system, forming an EEG headset. In oneimplementation, the system 100 can include an electrode body defining anelectrode body 120 that can include a base, a cavity, an annulus, anelectrode tip 130, a conductive element (e.g., a flexible PCB), anelectrode interface 122, a spring element receiver 126, and anelectrical circuit 123 (e.g., a local signal circuit). The conductiveelement can be electrically coupled to and configured to transmit databetween the electrical circuit and a controller 102. The housing is alsoconfigured to retain (or “lock”) a set of spring elements 104 withinspring element receivers 126 of the base. The system includes a set ofspring elements 104 configured to: mechanically couple adjacentelectrode bodies 120; to expand and contract to accommodate differenthead sizes and shapes; and to locate adjacent electrodes 120 in relativepositions that approximate an EEG standard (e.g., the 10-20 system). Thesystem can include a controller 102 configured to receive electricalsignals from the set of electrode bodies 105, process the electricalsignals to produce an output, and transmit the output to an outputdevice (e.g., a monitor or a computer) to further process, analyze, ordisplay the output to a user or operator.

In another implementation, as shown in FIGS. 1-3B, the system 100includes a headset 101 defining a set of electrode bodies 105 configuredto detect electroencephalographic signals from the head of the user; anda set of spring elements 104 elastically interconnecting a set ofelectrode bodies 105 and configured to locate the set of electrodebodies 105 on the head of the user. Each spring element 110 in the setof spring elements 104 can include a spine 111 defining: a proximal end112 including a first arcuate section 113 extending about a first axis,configured to elastically deform about the first axis to accommodate acurvature of the head of the user, and configured to electrically coupleto a first electrical circuit 123 within a first electrode body 120 inthe set of electrode bodies 105; a distal end 114 including a secondarcuate section 115 extending about a second axis, configured toelastically deform about the second axis to accommodate the curvature ofthe head of the user, and a second electrical connector configured toelectrically couple to a second electrical circuit 123 within a secondelectrode body 120 in the set of electrode bodies 105; and a centersection 116 defining a serpentine geometry extending between theproximal end 112 and the distal end 114, and configured to elasticallydeform between the first axis and the second axis to accommodate a sizeof the head of the user. Each spring element 110 in the set of springelements 104 further includes a conductive element 117, extendingbetween the proximal end 112 and the distal end 114, along the centersection 116, and configured to conduct electrical signals between thefirst electrode body 120 and a second electrode body 120.

In yet another implementation, as shown in FIGS. 1-3B, the system 100includes a headset 101 defining a set of electrode bodies 105 and a setof spring elements 104. Each electrode body 120 in the set of electrodebodies 105 includes: a housing 121 defining an electrode interface 122configured to receive an electrode tip 130; and an electrical circuit123 arranged within the housing 121 and electrically coupled to theelectrode interface 122. Each spring element 11 in the set of springelements 104 defines a serpentine geometry extending between a firstelectrode body 120 and a second electrode body 120 in the set ofelectrode bodies 105 and is configured to: elastically deform betweenthe first electrode body 120 and the second electrode body 120; andcommunicate electrical signals between a first electrical circuit 123 inthe first electrode body 120 and a second electrical circuit 123 in thesecond electrode body 120. The system 100 further includes a set ofelectrode tips 106, each electrode tip 130 in the set of electrode tips106 defining: an electrode base 131 defining a conductive material,configured to transiently install on the housing 121, and configured toelectrically couple to the electrode interface 122; an elastic beam 132including the conductive material and extending from the electrode base131; a conductive probe 134 arranged on a distal end of the elastic beam132 opposite the electrode base 131, defining a first contact area 135configured to contact and electrically couple to the head of the user,and configured to conduct electrical signals from the head of the userto the electrode interface 122 via the elastic beam 132 and theelectrode base 131; and a boss 136 including an insulative material,extending from the electrode base 131 opposite the electrode interface122, and defining a second contact area 137 greater than the firstcontact area 135, configured to contact the head of the user, and totransfer a weight of the headset 101 to the head of the user.

2. Applications

Generally, the system includes a set of unique components (i.e., springsand electrodes) assemblable into a headset (e.g., an EEG headset)configured to locate a constellation of electrode bodies 106 accordingto an EEG standard (e.g., the 10-20 system) for a population of usersexhibiting different head shapes and sizes. In particular, the systemincludes a set of spring elements 104 interposed between and configuredto connect a set of electrode bodies 105. The set of spring elements 104exhibit different characteristic springs rates and are distributedacross the headset 101 to absorb different head sizes.

Generally, the headset 101 includes a set of electrodes constructed fromminimal parts. Electrode bodies and spring elements can be formed froman injection molded polymer. The headset 101 can be quickly assemblableand configurable by an operator with limited skill. Spring elements canattach to electrodes via interference fit. When assembled, the headset101 requires minimal adjustment to locate electrodes according to an EEGstandard. Therefore, the headset 101 can be quickly deployed to recordan accurate EEG result with limited operator skill. The spring element110 can be arranged in a serpentine shape to construct a flat spring andcan include a hollow channel. The hollow channel can contain a cablewithin the spring element 110 connecting adjacent electrodes. The springelement 110 can be arranged such that adjacent and nominally-parallelsections of the spring element 110 are offset, and each return end of aspring element 110 maintains a gap between the adjacent section and thereturn end to reduce or eliminate pinch points that may catch or pull ona user's hair while wearing the headset 101. The flat spring can restagainst the user's head and distribute the weight of the headset suchthat the entire weight of the headset is not carried solely by thecontact of the electrode tip 130 s against the user's scalp. Further,due to minimal weight and number of parts, the headset imparts minimalpressure to a user's head via the electrode tip 130 s and springelements, allowing the user to wear the headset for an extended periodof time with minimal discomfort. Additionally, the minimal constructionof the headset allows a user to freely assume a variety of positions(e.g., sitting, standing, or lying down) or move their head whilewearing the headset 101. Components providing functions such asprocessing and power can be located in a controller 102 external fromthe headset.

2.1 Spring Element Longitudinal Extension and Angular Flexion

Each spring element 110 in the set of spring elements 104 is configuredto elastically deform along a longitudinal axis according to a springrate to conform to the size of a user's head when locating the set ofelectrode bodies 105. The spring rate of each spring element 110 in theset of spring elements 104 is tuned such that extension of each of thespring elements 110 results in a controlled ratio of expansion betweenadjacent electrode bodies 120, which corresponds to positions ofelectrodes as defined by an EEG standard (e.g., international 10-20standard). Each spring element 110 interconnects two adjacent electrodebodies 120 and exhibits a spring rate matched to the expansion ratiobetween the two adjacent electrode bodies 120 according to the EEGstandard. Generally, spring elements 110 are configured to exhibitdifferent spring rates based on the number of loops (or turns) of theserpentine geometry. Additionally a spring element 110 can be configuredto exhibit a spring rated based on the cross-sectional area of thespring element 110, and/or the elasticity of the material of the springelement 110. The set of spring elements 104 includes multiple springelements 110 exhibiting multiple spring rates, and each spring element110 in the set of spring elements 104 is configured to cooperate withother spring elements 110 in the set of spring elements 104 to locatethe set of electrode bodies 105 according to an EEG standard for a rangeof head sizes without reconfiguration (e.g., without changing orreplacing spring elements 110.)

Spring elements 110 can additionally include a set of arcuate sectionsconfigured to elastically deform along an angular direction to conformto the curvature of a user's head. Additionally, the spring elements 110can elastically deform through a range of angles to accommodate a rangeof curvatures (e.g., multiple curvatures of multiple heads, multiplelocal curvatures of a single head). The set of arcuate sections caninclude a proximal arcuate section 113 and a distal arcuate section 15located at opposite ends of a center section 116 of the spring element110 defining the serpentine geometry. Spring elements 110 canelastically deform along the angular direction independent of thelongitudinal axis, and vice-versa, thereby decoupling the longitudinalmovement enabled by the longitudinal elastic deformation of theserpentine geometry and angular movement enabled by the angular elasticdeformation of the proximal arcuate end 113, the distal arcuate end 115,or both. Therefore spring elements 110 can conform individually to thesize and/or curvature of a user's head.

Each spring element 110 includes a spine 111 exhibiting the spring rateof the spring element 110 (longitudinal and angular) extending from aproximal end 112 to a distal end 114, and a conductive element 117defining a flexible PCB mounted to the spine 111. The conductive element117 extends between a proximal end 112 and a distal end 114 of the spine111 and extends from the proximal end 112 to form a proximal electricalconnector and extends from the distal end 114 to form a distalelectrical connector. The conductive element 117 is configured toconduct electrical signals between the proximal electrical connector andthe distal electrical connector while elastically deforming according tothe elastic deformation of the spine 111. Spring elements 110 includingan odd number of turns of the serpentine geometry can include theconductive element 117 mounted to one side of the spine 111 of thespring element 110 to position the proximal electrical connector in anorientation to interface with the electrical receiver of a first housing121 and position the distal electrical connector in an orientation tointerface with the electrical receiver of a second housing 121. Springelements 110, including an even number of turns of the serpentinegeometry, can include the conductive element 117 mounted to a first sideof the spine 111 and a second side of the spine 111 and include atransition from the first side to the second side. The conductiveelement 117 is mounted to the first face of the spine 111 to positionthe proximal electrical connector in an orientation to interface withthe electrical receiver of a first housing and the conductive element117 is mounted to the second face of the spine 111 to position thedistal electrical connector in an orientation to interface with theelectrical receiver of a second housing. Additionally, each springelement 110 is covered (e.g., dip molded, over molded, spray coated,cast) with an insulative and/or protective material to insulate and/orprotect the spine 111 and conductive element 117.

2.2 Distribution of Headset Weight Via Electrode Tips

The electrode tip 130 includes an elastic beam 132, a conductive probe134 cantilevered on a distal end of the elastic beam 132, and a boss136. The conductive probe 134 defines a first contact area 135,configured to contact and electrically couple to the scalp of the user.The boss 136 defines a second contact area 137, greater than the firstcontact area 135. The electrode tip 130 is configured to rest againstthe head of the user either on the hair, on the skin of the head, (suchas on the forehead) or directly on the scalp (in the case of a balduser) and carry a local portion of the weight of the headset 101 to thehead of the user via the boss 136. The conductive probe 134 is arrangedcantilevered on the distal end of an elastic beam 132 exhibiting aspring rate. The elastic beam 132 is configured to drive the conductiveprobe 134 toward the head of the user in a resting position. The boss136 resting on the head of the user decouples the local weight of theheadset 101 from the force of the elastic beam 132, driving theconductive probe 134 toward the head of the user, thereby limiting theforce exerted by the first contact area 135 of the conductive probe 134on the head of the user to the force exerted by the elastic beam 132corresponding to the spring rate of the elastic beam 132.

In one example in which the user has hair, the conductive probe 134passes between individual hairs of the user and contacts the scalp ofthe user beneath the hair. The force of the elastic beam 132 issufficient to maintain the conductive probe 134 in contact with the headof the user, thereby maintaining an electrical coupling between theconductive probe 134 and the head of the user. The weight of the headset101 is carried to the head of the user via the larger second contactarea 137 of the boss 136, and only the force exerted by the elastic beam132 is applied to the conductive probe 134 and, thereby to the user.

In another example, the electrode tip 130 is positioned on a region ofthe head of the user devoid of hair (e.g., the forehead, a bald scalp)and includes a recess 108 arranged between a first boss 136 and a secondboss 136. The elastic beam 132 is configured to guide the conductiveprobe 134 into the recess 138 in response to the scalp of the user incontact with the second contact area 137 of the first boss 136. Thelocal weight of the headset 101 is carried to the head of the user viathe second contact area 137 of the first boss 136 (and the secondcontact area 137 of the second boss 136) and decoupled from the forceexerted by the elastic beam 132 on the conductive probe 134 for alocation on the head of a user devoid of hair.

Therefore, the headset 101 equipped with a single electrode tipconfiguration can be applied to several users with heads of differenthair and scalp attributes, without customizing the headset 101 orinterchanging electrode tips 130 for each user, thereby reducing thenumber of headset configurations and electrode tip configurationsnecessary to electrically couple an electrode tip 130 effectively to thehead of a user.

In another implementation, the system 100 includes an electrode tip 130defining a unitary structure including a conductive probe 134 formedfrom a conductive polymer, and a boss 136 formed from an insulativepolymer. The electrode tip can be formed as a single injection moldedpolymer part including a first injection of the conductive polymer and asecond injection of the insulative polymer, the insulative polymerbonding to the conductive polymer during the injection molding process.The insulative polymer can be selectively bonded to the conductivepolymer to limit the exposed area of conductive polymer to electricalcontact surfaces (such as electrode contact surfaces or an electricalinterface between an electrode tip and an electrode housing.) Further,the conductive polymer can be integrated within the electrode housing toform an electromagnetic shield 124, isolating the local contact area ofan electrode tip from external electromagnetic interference, therebyincreasing the clarity of an EEG signal. The electrode tip 130 can beconfigured to transiently install in an electrode housing via magneticattachment allowing a rotational degree of freedom and enabling finetuning of the placement of the conductive probe on the head of the user.In one variation, the headset 101 includes a set of mass produced,single-use sanitary electrode tips 130 that can be discarded after anEEG of each user.

3. Electrode Bodies

As shown in FIG. 1 , the EEG headset includes a set of electrode bodies105 configured to locate at points of an EEG standard, such as theinternational 10-20 system. The set of electrode bodies can divide intosubsets. A first subset of (e.g., two) electrode bodies can arrange fivespring receivers (e.g., at 0°, 450, 90°, 1350, and 180° positions) and astrap connector (e.g., at 270° position) and can be configured to locateat T3 and T4 locations. A second subset of (e.g., three) electrodebodies can include four spring receivers (e.g., at 0°, 90°, 180°, and270° positions) and can be configured to locate at Fz, Cz, and Pzlocations. A third subset of (e.g., two) electrode bodies an includethree spring receivers (e.g., at 0°, 90°, and 180° positions) and can beconfigured to locate at FpZ and Oz locations. A fourth subset of (e.g.,fourteen) electrode bodies can include two spring receivers (e.g., at 0°and 180° positions) and can be configured to locate at Fp1, F7, T5, O1,O2, T6, F8, Fp2, F3, F4, C3, C4, P3, P4, locations.

In one implementation, an electrode body 120 can include a base with acastellated perimeter wall encircling a cavity and defining a set ofspring receivers, and an annulus facing downwardly from the cavityopposite the spring receivers and configured to receive an electrode tip130. An electrical circuit 123 can be arranged in the cavity over theannulus. An electrode interface 122 can be arranged on the housing 121and is configured to electrically couple to an electrode tip 130. Theelectrical circuit 123 (e.g., a local signal circuit, an amplifiercircuit) can be arranged within the housing 121 and configured to readand condition an EEG signal from the electrode tip 130. A connector canbe arranged on the electrical circuit 123 and configured to transmitdata received from the electrical circuit 123 to a controller 102, andto receive power input. A cover can be arranged over the base over thecavity and configured to enclose the electrical circuit 123 within thecavity and retain (or “lock”) a set of springs within the springreceivers of the base. For example, the cover can interface with thecastellated perimeter wall of the base to construct a spring receiver,and a spring element 110 can insert into the spring receiver in aninterference (or “snap”) fit. An annular cushion can be arranged on thebase about the annulus and opposite the cover and configured to carryweight of the electrode to a scalp. For example, the annular cushion canbe an elastic material (e.g., silicone, memory foam) and can be bondedthe base about the annulus. In one variation, the system includes a kitof the annular cushions that are interchangeable to suit differentelectrode sizes. An electromagnetic shield 124 can be arranged withinthe housing 121 between the electrical circuit 123 and the cover andconfigured to shield an electrode tip 130 installed on the electrodeinterface 122 from ambient electrical noise.

In one implementation, the electrode body is formed from a conductivepolymer and an insulative polymer as a unitary structure. The electrodebody can include the housing 121 enclosing the electrical circuit 123,formed from the insulative polymer, and the electrode interfaceconfigured to receive and electrically couple to an electrode tip 130formed from the conductive polymer. Additionally, the housing 121 caninclude conductive polymer arranged to form an electromagnetic shield124 configured to shield the electrode tip 130, and the local area ofthe head of the user to which the electrode tip 130 is electricallycoupled, from external electromagnetic radiation.

For example, as shown in FIG. 2C, the electrode body 120 defines aunitary structure and includes a housing 121 formed from an insulativepolymer; an electrode interface 122 formed from a conductive polymer;and an electromagnetic shield 124 formed from a conductive polymer,extending from the electrode interface 122 toward the head of the user,radially offset from and encircling the boss 136, and configured toshield the conductive probe 134 from external electromagnetic radiation.

Therefore, the electromagnetic shield 124 can reduce extraneouselectromagnetic noise by shielding the electrode tip 130 and the localarea of the head of the user to which the electrode tip 130 iselectrically coupled, thereby resulting in a higher quality signal fromthe electrode tip 130. In particular, the electromagnetic shield canreduce undesirable artefacts in the EEG such as electrical mainsartifacts or capacitive coupling artifacts (e.g., sudden movements,waving hands around the user).

In another implementation, the electrical circuit 123 includes a lightelement (e.g., a multi-color LED, a light ring) arranged on the housing121. A controller 102 (described below) can implement methods andtechniques described in application number U.S. Ser. No. 15/351,016which is incorporated by reference, to: track contact quality between anelectrode tip 130—installed in the electrode body 120—and a user'sscalp; set the light element to a first color (e.g., green) if contactquality of the electrode tip 130 exceeds a threshold contact quality;set the light element to a second color (e.g., yellow) if contactquality of the electrode tip 130 is varying at greater than a thresholdfrequency; and/or set the light element to a third color (e.g., red) ifcontact quality of the electrode tip 130 is less than the thresholdcontact quality.

3.1 Electrode Tip

Generally, an electrode tip 130 cooperates with an electrode body 120and an electrical circuit 123 arranged within the electrode body 120 todefine an “electrode.” The electrode is configured to contact the skinof a user, to detect local neural oscillations on the user's skin, andto transmit data representing these local neural oscillations to thecontroller 102. For example, the electrode can detect a high-impedancesense signal from the user's skin; convert this high-impedance sensesignal into a low-impedance sense signal; and pass this low-impedancesense signal to the controller 102 via a wired connection passingthrough one or a series of spring elements between the electrode and thecontroller 102. The electrode can be formed from a conductive material(i.e., metal, non-metallic, conductive foam, conductive polymer). Thesystem can include a kit of electrode tips 130 that are electricallyconductive, configured to transiently install in the set of electrodebodies 105, and defining a set of configurations such as: flat or domed(e.g., for no hair), short bristles (e.g., for short, thin, and/orstraight hair), or long bristles (e.g., for long, voluminous, curlyhair).

In one implementation as shown in FIGS. 2A-2C, the electrode tip 130includes a conductive probe 134 mounted to the distal end of an elasticbeam 132 configured to extend the conductive probe 134 from theelectrode base 131 toward the surface of the head of the user. Theconductive probe 134 is formed from a conductive material (e.g., aconductive polymer) and defines a first contact area 135 at the tip ofthe conductive probe 134. The conductive probe 134 defines a smallcross-section relative to the length of the conductive probe, (e.g., aneedle-like structure) to pass through the hair of a user and contactthe skin of the user's scalp via the first contact area 135. Theelectrode tip 130 further includes a boss 136 formed from an insulativematerial (e.g., an insulating polymer) extending from the electrode base131, defining a larger cross-section relative to the length of theextension of the boss 136 from the electrode base, and defining a secondcontact area 137 larger than the first contact area 135. The electrodetip 130 further includes a recess 138, proximal the boss 136, into whichthe conductive probe 134 retracts when under a load produced by contactwith the head of a user.

For example as shown in FIGS. 2A-2C, the electrode tip 130 includes anelastic beam 132 coupled to the electrode base 131 via a flexion joint133 configured to: extend the conductive probe 134 toward the surface ofthe head in an unloaded state; and retract the first contact area 135 ofthe conductive probe 134 into a recess 138 adjacent the boss 136 in aloaded state.

In another example, the system 100 includes an electrode tip 130 furtherincluding a central electrode tip: extending from the electrode base;defining a third contact area configured to contact and electricallycouple to the head of the user; including the conductive polymer exposedat the third contact area and extending to and electrically coupling tothe electrode base; including the insulative polymer bonded to andencasing the conductive polymer between the third contact area and theelectrode base; and configured to contact and conduct electrical signalsfrom the head of the user to the first electrode interface via the firstelectrode base.

In another example, the system 100 includes an electrode tip 130including: an elastic beam 132 mounted to an electrode base 131 at aproximal end and including the conductive polymer; a conductive probe134 mounted to the elastic beam 132 at a distal end, including theconductive polymer extending from a first contact area 135 to theelastic beam 132, and configured to electrically couple the firstcontact area 135 to the electrode base 131 via the elastic beam 132. Theelectrode tip 130 further includes a boss 136: separately mounted to theelectrode base 131 radially offset from the conductive probe 134 and theelastic beam 132; including the insulative polymer; and extending fromthe electrode base 131.

In another example, the electrode tip 130 defines a unitary structureincluding: an electrode base including the conductive polymer,configured to transiently install on the housing, and configured toelectrically couple to the electrode interface; an integrated elasticbeam extending from the electrode base including the conductive polymerand the insulative polymer bonded to and encasing the conductive polymerbetween the electrode base and a distal end; an integrated conductiveprobe arranged at a distal end of the elastic beam opposite theelectrode base, defining a first contact area configured to contact andelectrically coupled to the head of the user, configured to conductelectrical signals from the head of the user to the electrode interfacevia the elastic beam and the electrode base, including the conductivepolymer extending from the first contact area to the distal end, andincluding the insulative polymer bonded to and encasing the conductivepolymer between the first contact area and the elastic beam; and anintegrated boss including the insulative polymer, extending from theelectrode base opposite the electrode interface, and defining a secondcontact area greater than the first contact area, configured to contactthe head of the user, and to carry a weight of the headset to the headof the user.

In one variation, the electrode tip can include multiple conductiveprobes 134 cooperating to increase the surface area of the electrode tip130 in contact with an electrically coupled to the head of a user, andmultiple bosses 136 to increase to increase the surface areatransferring the weight of the headset to the head of the user. Theelectrode tip 130 conductive probes 134 and bosses 136 arranged in aradially symmetrical pattern, with the gaps between the bosses 136forming the recesses 138.

In one example, the electrode tip 130 additionally includes: a secondelastic beam 132 arranged circumferential to the first elastic beam 132,including the conductive material and extending from the electrode base131; and a second conductive probe arranged on a distal end of thesecond elastic beam opposite the first electrode base, defining a thirdcontact area configured to contact and electrically couple to the headof the user and configured to conduct electrical signals from the headof the user to the first electrode interface via the second elastic beamand the first electrode base. The electrode tip 130 additionallyincludes a second boss, circumferential to the first boss: including theinsulative material; extending from the first electrode base oppositethe first electrode interface; and defining a fourth contact areagreater than the third contact area, configured to contact the head ofthe user, and to carry a weight of the headset into the head of theuser.

The electrode tip 130 is configured to contact the head of a user suchthat the boss 136 rests on the head of the user, either on the hair, onthe skin of the head, (such as on the forehead) or directly on the scalpin the case of a bald user. In one example in which the user has hair,the conductive probe 134 pierces the hair of the user and contacts thescalp of the user beneath the hair. The conductive probe 134 experiencesresistance as it contacts the scalp of the user. In response, theelastic beam 132 deforms under this resistance, and the conductive probe134 retracts toward the electrode base 131 and partially into the recess138. The force of the elastic beam 132 is sufficient to maintain theconductive probe 134 in contact with the head of the user, therebymaintaining an electrical coupling between the conductive probe 134 andthe head of the user. However, the weight of the headset 101 istransferred to the head of the user via the larger second contact area137 of the boss 136. The elastic beam 132 may not deform at all when theelectrode tip 130 is positioned on the head of a user with particularlylarge volume of hair.

In another example in which the local area to which the electrode tip130 is in contact does not include hair (e.g., the forehead, the head ofa bald user), an electrode tip 130 includes a conductive probe 134 of alength equal to the length of the boss 136, such that under a load, theconductive probe 134 will retract entirely into the recess 138, andtherefore the first contact area 135 of the conductive probe 134 and thesecond contact area 137 of the boss 136 will be coplanar (e.g., bothresting against the scalp of the user). As the conductive probe 134contacts the scalp of the user and experiences resistance, the elasticbeam 132 deforms under this resistance in response, and the conductiveprobe 134 retracts toward the electrode base 131 completely into therecess 138. The second contact area 137 of the boss 136 transfers theweight of the headset to the user, while the first contact area 135 ofthe conductive probe 134 is held against the head of the user by theforce of the elastic beam alone. This results in a comfortableexperience for the user, as the weight of the headset 101 is distributedacross the larger second contact area 137, rather than entirelyconcentrated at the first contact area 135 of the conductive probe 134.

Therefore, a single electrode tip configuration can be applied toseveral user types with different hair and scalp attributes, or to auser with multiple hair patterns across their head (e.g., recedinghairline, bald spot) without customizing the headset 101 orinterchanging electrode tips 130 of different configurations, therebyreducing the number of electrode tip configurations necessary toelectrically couple an electrode effectively to the head of a user.

3.2 Mechanical Coupling

In one implementation, the electrode interface 122 of an electrode body120 defines a retention aperture above and centered over the annulus ofthe electrode body 120, and an electrical trace adjacent and/orencircling the retention aperture. In this implementation, an electrodetip 130 includes an electrode base 131 configured to seat in an annulusof an electrode body 120, a contact end arranged on a distal end of theelectrode base 131 opposite the electrode body 120 and configured tocontact a scalp of a user, and a barb extending rearward from theelectrode base 131 and configured to insert into and retain theretention aperture of the electrode interface 122 in the electrode body120. For example, the electrode base, the contact end, and the barbdefine a unitary elastic structure (e.g., an injection-molded polymer)autocatalytically coated with a conductive material (e.g., nickel). Thebarb can be elastic and can deform when inserted into the retentionaperture and can expand behind the electrode interface 122 to retain theelectrode within the aperture of the electrode body 120 and maintainmechanical contact and electrical connectivity between the electrodebase 131 and the electrical trace adjacent the retention aperture.Therefore, the retention aperture of the electrode interface 122 and thebarb of the electrode tip 130 can cooperate to mechanically retain theelectrode tip 130 within the electrode body 120 and to maintainelectrical contact between electrical trace on the electrode interface122 and the electrode tip 130. For example, to install the electrode tip130 in the electrode body 120, a user pushes the electrode tip 130 intothe annulus of the electrode body 120 to seat the barb in the retentionaperture. To replace the electrode tip 130, a user pulls the electrodetip 130 out of the electrode body 120. Furthermore, minimal parts areneeded to construct the electrode. The barb is molded into the electrodebase, and the retention aperture is fabricated directly into theelectrode interface 122 at time of manufacture.

3.3 Magnetic Coupling

In another implementation, the electrode interface 122 of an electrodebody 120 defines an electrical trace facing the annulus. The electrodebody 120 further includes a magnet, such as centered on the electrodeinterface 122 over and opposite the annulus. The electrode tip 130includes an electrode base 131 configured to seat in an annulus of anelectrode body 120, and a magnetic element (e.g., an iron insert)arranged in the electrode base.

In one example, the electrode body 120 defines a housing including afirst magnetic element arranged at the electrode interface 122; and theelectrode tip 130 includes an electrode base 131 defining a secondmagnetic element configured to transiently couple to the first magneticelement to retain the electrode tip 130 on the housing 121 via amagnetic connection and rotate freely about an axis perpendicular to theelectrode interface 122.

In another example, the electrode base, contact end, and the magneticelement can define a unitary structure autocatalytically coated with aconductive material (e.g., nickel). The magnetic element is a magneticmaterial (e.g., Iron or steel). Magnetic polarity is configured suchthat the magnetic element is magnetically attracted to the magnet withinthe electrode body 120. Magnetic attraction between magnet and magneticelement can function to retain the electrode within the aperture of theelectrode body 120 and maintain mechanical contact and electricalconnectivity between the electrode base 131 and the electrical traceadjacent the retention aperture. Therefore, the magnet and the magneticelement can cooperate to constrain the vertical position of theelectrode tip 130 within the electrode body 120. The annulus and theelectrode base 131 can cooperate to constrain the lateral position ofthe electrode tip 130 within the electrode body 120. For example, toinstall the electrode tip 130 in the electrode body 120, the user placesthe electrode tip 130 in the annulus of the electrode body 120 tomagnetically couple the magnetic element in the electrode to the magnetin the electrode body 120. To replace the electrode tip 130, the userpulls the electrode tip 130 out of the electrode body 120. Furthermore,minimal parts are needed to construct the electrode. The magneticelement is permanently fixed to the electrode tip 130, and the magnet isfixed within the electrode body 120 at time of manufacture.

3.4 Electrode Tip Geometry

In one implementation, each electrode defines a dry EEG electrodeincluding a substrate, a set of electrically conductive bristles (e.g.,short bristles, long bristles or a flat or domed conductive end), and anamplifier coupled to the substrate opposite the electrically conductivebristles. In another implementation, the electrode tip 130 defines aconductive probe 134 configured to electrically couple to the head ofthe user and an insulative boss 136 configured to contact the head ofthe user and transfer a weight of the headset into the head of the user.

3.5 Photosensor Housing

In one variation of an electrode body 120, the cover defines a coveraperture. The electrical circuit 123 includes a light sensor element(e.g., photodiode, bipolar phototransistor, or photoFET) proximal thecover aperture. The light sensor element is configured to detect lightsignals corresponding to properties of light detected (e.g., intensity,color, frequency of pulses when using a strobe, time length of exposure,etc.), to convert these light signals into electrical signals, and totransmit these electrical signals to the controller 102 configured totrack and process light stimulation data, as described below. Thephotosensor housing can be interchanged with an electrode body 120 orbridge housing, as described below. For example, in this variation, theheadset can assemble with a photosensor housing in preparation for anEEG test specifying a strobe stimulus. Later, the headset can bereassembled without the photosensor housing, such as to reduce weight ofthe headset, to reduce complexity of the headset, or to replace thephotosensor housing with a vibratory housing including a vibrator inpreparation for an EEG test specifying a tactile stimulus.

3.6 Bridge Housing

In one variation, a housing includes elements to electrically connect toa set of spring elements 104. A bridge housing functions to connectelectrode bodies 105 adjacent to the bridge housing to one another. Abridge housing can include an electrical circuit 123 configured to boostor amplify an incoming signal and transmit this boosted signal as outputto the controller 102. Generally, a bridge housing 121 includes anannular cushion similar to other electrode bodies 120, and therefore canbe used to reduce the electrode pressure exerted on a user's scalp by anadjacent electrode body 120 by supporting some of the weight of theadjacent electrode body 120.

3.7 External Connection Housing+Chinstrap

Generally, the external connection housing includes an externalconnection to a controller and power source. The headset 101 includes anexternal connection to transmit data and receive power. An externalconnection cable connects the external connection housing to thecontroller 102. Signals from the set of electrode bodies 105 passthrough this external connection cable to the controller 102. In oneimplementation, the external connection and chinstrap housing arephysically coextensive, and the system includes external connection andchinstrap housings at the T3 and T4 locations.

In another implementation, the external connection housing can be placedat the O1 and O2 locations, and the external connection cable or cablesrouted to the controller 102. However, the external connection housingmay be placed in any location to maximize the quality of the electricalsignals transmitted from the EEG headset based on the user's position.

In one variation, a body of an electrode body 120 configured forarrangement near a user's temple (e.g., a T3 or T4 position) furtherincludes a strap receiver configured to selectively receive and retain adistal end of an adjustable chinstrap.

Generally, securing the headset to the user can be necessary duringrecording of an EEG. Due to the sensitivity required to accuratelymeasure local neural oscillations on the skin to record an accurate EEG,it is desirable that electrode tips 130 do not move relative to theirinitial position on the head of the user during the EEG recording. Toreduce undesirable movement of the electrode tips 130 during an EEGmeasurement, a securement strap (e.g., a chin strap, a flexible jawstrap, a chest strap) is secured to one or more electrode bodies 120 andsecured to the user.

In one example, the system can include a T3 electrode body 120 defininga first strap receiver; a T4 electrode body 120 defining a second strapreceiver; a first insert pivotably coupled to a proximal end 112 of theadjustable chinstrap and configured to insert into the first strapreceiver and to fixedly couple the proximal end 112 of the adjustablechinstrap to the T3 electrode body 120; and a second insert pivotablycoupled to a distal end 114 of the adjustable chinstrap; configured toinsert into the second strap receiver and to fixedly couple the distalend 114 of the adjustable chinstrap to the T4 electrode body 120.

In another example, a first electrode body 120 includes an electrode tip130 in contact with the head of the user positioned at a first mastoidreference proximal a first ear of the user; a second electrode body 120includes an electrode tip 130 in contact with the head of the userpositioned at a second mastoid reference proximal a second ear of theuser and includes an accelerometer 127; and the controller 102 iselectrically coupled to the headset 101 via the second electrode body120. The accelerometer is configured to measure movement of the head ofthe user (e.g., during a seizure or other involuntary movement) duringan EEG measurement and transmit signals describing measured movement tothe controller.

Therefore, by connecting the controller 102 to the headset 101 via anelectrode body 120 located at the side of the head of the user (e.g.,T3, T4) the system 100 enables the user to lie down on their back ortheir side (opposite the connection to the controller) without trappingthe external connection cord between the user and the surface of the bedand causing discomfort. Thereby the user can participate in an extendedEEG test, such as a sleep study, with a greater level of comfort.

3.8 Electrode Housing Position

In one implementation, the EEG headset includes a set of electrodesconnected via a set of spring elements 104 and arranged in theinternational 10-20 pattern. A first subset of (e.g., two) electrodebodies can include five spring receivers (e.g., at 0°, 45°, 90°, 135°,and 180°. positions) and a strap connector (e.g., at 270° position) andcan be configured to locate at T3 and T4 locations. A second subset of(e.g., three) electrode bodies can include four spring receivers (e.g.,at 0°, 90°, 180°, and 270° positions) and can be configured to locate atFz, Cz, and Pz locations. A third subset of (e.g., two) electrode bodiescan include three spring receivers (e.g., at 0°, 90, and 180°.positions) and can be configured to locate at FpZ and Oz locations. Afourth subset of (e.g., fourteen) electrode bodies can include twospring receivers (e.g., at 0° and 180°. positions) and can be configuredto locate at Fp1, F7, T5, O1, O2, T6, F8, Fp2, F3, F4, C3, C4, P3, P4,locations. At position T3, a 5-position electrode body 120 can beconnected to 4 spring elements, one chin strap, and an externalconnection cable. At position T4, a 5-position electrode body 120 can beconnected to 4 spring elements and one chin strap. At positions Fz, Cz,and Pz, a 4-position electrode body 120 can be connected to adjacentelectrodes via a spring element 110 arranged along a medial and lateralplane. In this implementation, at positions Fp1, F7, T5, O1, O2, T6, F8,and Fp2, a 2-position electrode body 120 can be connected to adjacentelectrodes via a spring element 110 along a circumferential path. Atpositions F3, F4, C3, C4, P3, and P4, a 2-position electrode body 120can be connected to adjacent electrodes via a spring element 110 along alateral path. At position Fpz, a 3-position photosensor housing 121 canbe connected to adjacent electrodes along the medial plane and thecircumferential path. In one variation, the housing 121 located at Fpzis a 2-position photosensor housing 121 connected to adjacent electrodesalong a circumferential path. In another variation, the housing 121located at Fpz is a bridge housing 121. In another variation, thehousing 121 located at Fpz is an electrode body 120. At position Oz, a3-position bridge housing 121 can be connected to adjacent electrodesalong the medial plane and the circumferential path. In one variation,the housing 121 located at Oz is a 2-position bridge housing 121connected to adjacent electrodes along a circumferential path. In onevariation, a 2-position electrode body 120 can be connected to adjacentelectrodes via a spring element 110 arranged along a lateral plane atpositions Fz, Cz, and Pz. In another variation, the housing 121 locatedat Oz is an electrode body 120.

However, the EEG headset can include a set of electrodes connected via aset of spring elements 104 and arranged a pattern other than theinternational 10-20 standard pattern or include additional housings 121(and necessary spring elements to support) in other locations on thehead.

3.9 Additional Housing Configurations

As described above, each electrode body 120 can include a baseconfigured for assembly within a singular electrode position or within asmall subset of electrode positions. Therefore, the system can includegroups of unique electrode bodies 120.

Conversely, a first electrode body 120 of the system can include a baseidentical to the base of a second electrode body 120 and can includereceiving element positions configured to receive and retain allpermutations of spring elements, chin strap receivers, and externalcable combinations to form a complete 10-20 EEG headset. For example,each electrode body 120 can include a set of receiving elementspositioned in a radially-symmetrical pattern at 0°, 45°, 90°, 135°,180°, 225°, 270°, and 315° positions. In this example, a system canfurther include a set of inserts configured to locate within and encloseunused receiving elements within electrode bodies of the headset, suchas to prevent hair entanglement within these unused receiving elements.

In one implementation, the electrode body 120 can be configured toorient spring elements at an oblique angle to the housing 121 toaccommodate the curvature of the head of the user. For example, anelectrode body 120 can define a housing 121 including a spring elementreceiver 126 arranged at a circumferential surface 125 of the housing121 and configured to connect a spring element 110 to the housing 121 atan oblique angle. In one variation, the oblique orientation of thespring element receiver 126 cooperates with the angle of an arcuatesection of the spring element 110 to create an angle between the springelement 110 and the housing 121 that best matches the curvature of thehead of a multitude of users, thereby producing a headset 101 that ismore comfortable for the multitude of users.

4. Spring Elements

Generally, the system includes a set of spring elements 104 configuredto: mechanically couple adjacent electrodes; to expand and contract toaccommodate different head sizes and shapes; and to locate adjacentelectrodes in relative positions that approximate an EEG standard (e.g.,the 10-20 system).

In one implementation, a spring element 110 is arranged in a serpentineshape to construct a flat spring. In particular, the spring element 110is arranged in a boustrophedonic pattern, with the spring element 110extending in a first direction, curving 90°, and extending a distance ina second direction perpendicular to the first direction, subsequentlycurving 180° and extending in a third direction parallel and oppositethe second direction, subsequently curving 180° and extending in thesecond direction, subsequently curving 90° and extending in the firstdirection. Furthermore, adjacent and nominally-parallel sections of thespring element 110 are offset and each return end of a spring element110, characterized by a large and smooth curve, maintains a gap betweenthe adjacent section and the return end to reduce or eliminate pinchpoints that may catch or pull on a user's hair while wearing theheadset.

4.4 Linear Extension

In one implementation, the system 100 includes: a first spring element110 defining a first spine 111 exhibiting a first spring rate; and asecond spring element 110 defining a second spine 111 exhibiting asecond spring rate, different from the first spring rate. The firstspring element 110 cooperates with the second spring element 110 toconstrain the spacing of the set of electrode bodies 105 to repeatablylocate the set of electrode bodies 105 at a set of positions on a headof a user for a range of head sizes.

In one example, a first spring element 110 of a first spring rate isarranged between a first electrode body 120 located at the T3 electrodeposition and a second electrode body 120 located at the C3 electrodeposition, and a second spring element 110 of a second spring rate isarranged between the first electrode body 120 and a third electrode body120 located at the T5 electrode position. The first distance between theT3 electrode position and the C3 electrode position is greater than thesecond distance between the T3 electrode position and the T5 electrodeposition. Therefore, the first spring element 110 is required to extenda greater distance than the second spring element 110. The lower springrate of the first spring element 110 enables greater variation inposition between the electrode body 120 located at the T3 electrodeposition and the electrode body 120 located at the C3 electrodeposition, compared to the electrode body 120 located at the T3 electrodeposition and the electrode body 120 located at the T5 electrodeposition.

In another implementation, a first spring element 110 includes across-section of a first thickness, and a second spring element 110includes a cross-section of a second thickness less than the firstthickness. Accordingly, the second spring element 110 exhibits a lowerspring rate than the first spring element 110.

In another implementation, a first spring element 110 includes a firstnumber of turns and a second spring element 110 includes a second numberof turns less than the first number of turns. Accordingly, the secondspring element 110 extends less than the first spring element 110 when atension force is applied to the spring element 110, and the secondspring element 110 exhibits a lower spring rate than the first springelement 110.

In another implementation, a first spring element 110 includes a firstreturn radius, and a second spring element 110 includes a second returnradius less than the first return radius. Accordingly, the second springelement 110 exhibits a higher spring rate than the first spring element110.

In another implementation, a first spring element 110 includes a firstlength between turns, and a second spring element 110 includes a secondlength between turns that is less than the first length between turns.Accordingly, the second spring element 110 extends less than the firstspring element 110 when a tension force is applied to the spring element110 (e.g., exhibits a lower spring rate.)

In another implementation, a spring element 110 can incorporate a crosssection with a varying thickness or varying return radii in order toproduce different spring rates as a function of travel, to construct aspring element 110 with a non-uniform flex pattern.

4.2 Angular Flexion

In another implementation as shown in FIGS. 3A-3B, the spring element110 is configured with a first arcuate section 113, located at theproximal end 112, of a first elasticity, and a second arcuate section115, located at the distal end 114, of a second elasticity. The firstarcuate section 113 and the second arcuate section 115 enable the springelement 110 to flex in a second degree of freedom (e.g., angularflexion) in addition to the first degree of freedom (e.g., longitudinalextension via the serpentine geometry of the center section). Theangular flexion of the spring element 110 enables the headset 101 toconform more closely to the curvature of a user's head, increasingcomfort for the user, especially during periods of extended wear (e.g.,sleep study).

For example, a first spring element 110 with a first arcuate section 113of a first elasticity and a second arcuate section 115 of the firstelasticity, is arranged between a first electrode body 120 located atthe C3 electrode position and a second electrode body 120 located at theCz electrode position, and a second spring element 110 of a firstarcuate section 113 of a second elasticity and a second arcuate section115 of the second elasticity, is arranged between the first electrodebody 120 and a third electrode body 120 located at the T3 electrodeposition. The first curvature of the head of the user between the C3electrode position and the Cz electrode position is greater than thesecond curvature of the head of the user between the C3 electrodeposition and the T3 electrode position, therefore the first arcuatesection 113 and the second arcuate section 115 of the first springelement 110 are required to flex a greater distance than the firstarcuate section 113 and the second arcuate section 115 of the secondspring element 110.

In one implementation, the set of spring elements 104 includes a firstspring element 110 including a first arcuate section 113 of a firstelasticity; and a second arcuate section 115 of a second elasticity,greater than the first elasticity. The first spring element 110 isconfigured to mechanically couple to a first electrode body 120 proximalthe first arcuate section 113; locate the first electrode body 120proximal a first location on the head of a user exhibiting a firstcurvature; couple to a second electrode body 120 proximal the secondarcuate section 115; and locate the second electrode body 120 proximal asecond location on the head of a user exhibiting a second curvature,greater than the first curvature.

For example, a spring element 110 includes a proximal end 112 defining afirst arcuate section 113 of a first elasticity and a distal end 114defining a second arcuate section 115 of a second elasticity, greaterthan the first elasticity, is arranged between a first electrode body120 located at the T3 electrode position and a second electrode body 120located at the C3 electrode position. The curvature of the head of theuser proximal the C3 electrode position is greater than the curvature ofthe head of the user proximal the C3 electrode position. The springelement 110 is coupled to the first electrode body 120 at T3 via theproximal end 112 and is coupled to the electrode body 120 at C3 via thedistal end 114. The spring element 110 exhibits angular flexion at thesecond arcuate section 115 greater than the angular flexion exhibited atthe first arcuate section 113, based on the curvature of the head of theuser. Therefore, the spring element 110 can include a first arcuatesection 113 and a second arcuate section 115 configured to flexindependently to different angles of flexion to conform to the curvatureof the head of the user.

In another variation, the system 100 includes a set of spring elements104 including a first spring element 110 including: a first springelement defining a first proximal arcuate section bending by a firstangular amplitude, and a first distal arcuate section, bending by thefirst angular amplitude; and a second spring element defining a secondproximal arcuate section bending by a second angular amplitude, and asecond distal arcuate section, bending by the second angular amplitude.The first spring element cooperates with the second spring element toconstrain the angular flexion of a set of electrodes to repeatablylocate the set of electrodes at a set of positions on a head of a userfor a range of head shapes (e.g., whole head curvature, localcurvature).

In one example in which a local region of the head of the user exhibitsa low curvature (e.g., is flatter), the electrode bodies 120 located atthe Cz, and Pz electrode locations in the 10-20 system line arecolinear, and the electrode body 120 at Pz is oblique to the electrodebody at Cz. The spring element 100 includes a proximal end 112 with afirst arcuate section 113 defining a bend of 90 degrees between theserpentine geometry of the center section 116, and the electrode body120 at Cz, thereby arranging the electrode body 120 at Cz and the springelement 120 colinear. The distal end 114 of the spring element 120defines an oblique bend, and couples to the electrode body 120 at Pz tomatch the curvature of the head of the user.

Therefore, the first spring element 110 can flex a first angle at thefirst arcuate section 113 and a second angle at the second arcuatesection 115 to accommodate the curvature of a user's head. The degree offreedom enabled by the angular flexion of the flexible arcuate sectionsof the spring element 110 can enable the headset 101 to conform to thecurvature of the head of a user more closely. Further, the elasticity ofthe first arcuate section 113 and the second arcuate section 115 can beconfigured to conform to multiple curvatures to accommodate the heads ofmultiple users without reconfiguring the headset 101.

In another example in which the head of the user is of a first size, theheadset 101 includes: a first spring element defining a first centersection extended a first linear amplitude, a proximal end including afirst arcuate section bending by a first angular amplitude, and a distalend including a second arcuate end bending by a second angularamplitude; and a second spring element including a second center sectionextended a second linear amplitude greater than the first linearamplitude, a second proximal end including a third arcuate sectionbending by a third angular amplitude less than the first angularamplitude; and a second distal end including a fourth arcuate endbending by a fourth angular amplitude less than the second angularamplitude.

Therefore, the headset 101 can include the set of spring elements 104including spring elements 110 capable of extending through a range ofamplitudes that can accommodate a range of head sizes of multiple users,eliminating the need to reconfigure the headset 101 between applicationsto multiple users, or to customize the headset 101 for each particularuser.

4.3 Spring Element Manufacturing

In one implementation, a spring element 110 can be formed from aninjection molded polymer and can be arranged in a serpentine shape toform a flat spring. The spring element 110 also includes a channel thatcan receive a cable. In another implementation, the spring element 110can be formed from metal, plastic, or a composite material. In anotherimplementation, shown in FIGS. 3A-3B, the spring element 110additionally includes an insulative layer 119 encasing the conductiveelement 117 and center section 116 of the spring element 110. In oneexample, the insulative layer 119 is additionally water resistant.Further, the connection interface between the spring element 110 and theelectrode body 120, as well as any other gaps in the electrode body 120,are sealed to be water resistant, thereby enabling the headset to besubmerged in a liquid (e.g., soap and water, a disinfectant solution) tobe cleaned without disassembly.

4.4 Cable Routing

In one implementation, the spring element 110 includes a hollowcross-section constructing a traversable cavity from a proximal end 112of the spring element 110 to a distal end 114 of the spring element 110opposite the proximal end 112. A cable can be disposed within thecavity. In one variation, the spring element 110 includes a U-shapedcross-section open to the exterior of the spring element 110. Forexample, the open, U-shaped cross-section can enable an assembler toinsert a cable into the channel for ease of assembly, thus reducingassembly cost. In another variation, after a cable is inserted, thespring element 110 and the joint between the spring element 110 and theelectrode body 120 is hermetically sealed.

In another implementation, the spring element 110 defines a spine 111and a conductive element 117 defining a flexible PCB (e.g., flexibleprinted circuit/FCP) mounted to one face of the spine 111. Theconductive element 117 terminates at the proximal end 112 and the distalend 114 of the spring element 110 at an electrical coupling configuredto couple the conductive element 117 to the electrical circuit 123 of anelectrode body 120. For example, as shown in FIGS. 3A-3B, the springelement 110 includes: a center section 116 defining a spine 111; and aconductive element 117 defining a flexible printed circuit board coupledto and extending along the spine 111 between the proximal end 112 andthe distal end 114.

In another implementation, a conductive element 117 defining a flexiblePCB is mounted to one face of the spine 111 of a center section 116defining a two-loop serpentine. The flexible PCB is mounted to a firstface of the spine 111, and is connected to a first electrical couplingat the proximal end 112. Due to the geometry of the two-loop serpentine,the flexible PCB transitions to a second face of the spine, opposite thefirst face, to connect to a second electrical coupling at the distal end114. The flexible PCB transitions at a conductive element transfer 118located on the center section between the proximal end 112 and thedistal end 114. The conductive element transfer 118 defines a length offlexible PCB connected to a first section of the conductive element 117extending along the spine 111 to the proximal end 112, executing a 90degree turn toward an edge of the spine 111, curling over the edge ofthe spine to the second face, opposite the first face, executing asecond 90 degree turn toward the length of the spine 111, and connectedto a second section of the conductive element 117 extending along thespine to the distal end 114.

In one example, shown in FIG. 3B, the spring element 110 includes: acenter section including a first spine defining a two-loop serpentine;and a first conductive element defining a proximal connector extendingfrom the proximal end of the first spine and configured to electricallycouple to a first electrical circuit, a proximal section coupled to afirst face of the spine and extending from the proximal connector alonga first face of the spine, a conductive element transfer extendingbetween the proximal section over an edge of the spine between the firstface of the spine and a second face of the spine, a distal sectioncoupled to the second face of the spine and extending from theconductive element transfer along the second face of the spine, and adistal connector coupled to the distal section and extending from thedistal end of the first spine and configured to electrically couple to asecond electrical circuit. The spring element 110 can further include aninsulative layer encasing the conductive element and the spine.Additionally, the spring element 110 including a center section 116 withan even number of turns (e.g., 2, 4, 8, 12) includes a conductiveelement transfer 118.

In another implementation, the spring element 110 includes a centersection 116 including a spine 111 defining a three-loop serpentine. Theconductive element 111 is arranged on a first face of the spine andextends between the proximal end and the distal end. The spring element110 can further include an insulative layer encasing the conductiveelement and the spine. Due to the geometry of the three-loop serpentine,the conductive element transfer 118 is not required for the conductiveelement 117 to connect with the proximal electrical connector and thedistal electrical connector. Additionally, a spring element 110including a center section with an odd number of turns (e.g., 1, 3, 7,ii) includes the conductive element 117 mounted to only one face of thespine 111.

4.5 Spring Element Distribution and Tuning

Generally, the system can include a set of springs configured to connectadjacent electrodes and characterized by spring rates inverselyproportional to variances in the distances between adjacent electrodesnecessary to achieve the electrode standard (e.g., 10-20 EEG standard)across a population of users with different head sizes and shapes. Inparticular, in the international 10-20 system, the electrode at positionF3 can vary more than the electrode at position T5. A spring element 110with a first spring rate can connect the electrode at position F3 to theelectrodes at positions T3 and Fz, and a spring element 110 with asecond spring rate greater than the first spring rate can connect theelectrode at position T5 to electrodes at positions T3 and O1.Generally, an electrode located at a medial position (e.g., Fpz, Fz, Cz,Pz, and Oz) will remain on the medial plane as the headset flexes, andthe spring elements connected to either side of the electrode in thelateral direction can flex equally in both directions.

In one example, the system 100 includes a first spring element 110including a first spine 111 exhibiting a first spring rate correspondingto a first electrode spacing ratio of 10 percent of the distance acrossthe surface of a head of a user between a first landmark and a secondlandmark, and a second spring element 110 including a second spine 111exhibiting a second spring rate corresponding to a second electrodespacing ratio of 20 percent of the distance across the surface of a headof a user between the first landmark and the second landmark.

In one implementation, the EEG headset includes a set of electrodebodies connected by spring elements in a chain pattern. A chain patternof electrode body 120 and spring element 110 connections is defined as:a proximal end 112 of a first spring element 110 connected to a firstelectrode body 120, the distal end 114 of the first spring element 110connected to a second electrode body 120, a proximal end 112 of a secondspring element 110 connected to the second electrode body 120 oppositethe first spring element 110, and a distal end 114 of the second springelement 110 connected to a third electrode body 120, etcetera. A firstset of spring elements 104 with a first spring rate can connectelectrode bodies in the chain pattern as described above along acircumferential path around the user's head with the followingconnections: Fpz connected to Fp1, Fp1 connected to F7, F7 connected toT3, T3 connected to T5, T5 connected to O1, O1 connected to Oz, Ozconnected to O2, O2 connected to T6, T6 connected to T4, T4 connected toF8, F8 connected to Fp2, and Fp2 connected to Fpz. A second set ofspring elements 104 with a second spring rate less than the first springrate can connect the electrodes along a medial path in the followingpattern: Fpz connected to Fz, Fz connected to Cz, Cz connected to Pz,and Pz connected to Oz. A third set of spring elements 104 with thesecond spring rate can connect the electrodes along a lateral path inthe following pattern: T3 connected to F3, F3 is connected to Fz, Fzconnected to F4, and F4 connected to T4. A fourth set of spring elements104 with the second spring rate can connect the electrodes along alateral path in the following pattern: T3 connected to C3, C3 connectedto Cz, Cz connected to C4, and C4 connected to T4. A fifth set of springelements 104 with the second spring rate can connect the electrodesalong a lateral path in the following pattern: T3 connected to P3, P3connected to Pz, Pz connected to P4, and P4 connected to T4. In onevariation, the medial electrodes Fpz, Fz, Cz, Pz, and Oz are connectedto adjacent electrodes along lateral paths only (e.g., Fp1, Fp2; F3, F4)In another variation, a set of spring elements 104 of another springrate are used in the same connection patterns.

In another variation, a kit of spring elements includes a set of springelements 104 of various spring rates and is included with the EEGheadset. An operator can assemble electrode bodies and spring elementsinto a customized EEG headset unique to the user. However, the systemcan include a set of springs and electrode bodies configured in anypattern to connect the electrodes to maintain electrode position in the10-20 EEG standard.

5. Additional Support Member

In one implementation, the system can include an elastic support memberproximal to the circumference of the EEG headset maintain electrodeposition in the 10-20 EEG standard and arrest movement of the headset inrelation to the user's scalp if the user moves. For example, the elasticsupport member can be attached to an electrode body 120 at Fpz, passedaround the circumference of a user's head and attached to an electrodebody 120 at Oz, and then passed around the opposite side of the user'shead and attached to Fpz. In another variation, the elastic member canbe attached to a set of electrodes at Fpz (or an adjacent electrodeposition) and subsequently attached to a set of electrodes at Oz (or anadjacent electrode position).

6. Controller

In one implementation, the EEG headset includes a controller 102connected to an external connection housing 121 via the externalconnection cable, the controller 102 including: an electrical circuit, aprocessor, storage, memory, and an external device connection. Thecontroller 102 can be configured to receive electrical signals from theset of electrodes, process the electrical signals to produce an output,and transmit the output to an output device (e.g., a monitor or acomputer) to further process, analyze, or display the output.

In another example, a headset 101 worn by a user during a test can beconnected to the controller 102. The controller 102 can be connected toa monitor displaying the data output. As the test progresses, theelectrodes can produce electrical signals that are transmitted to thecontroller 102. The controller 102 then processes these electricalsignals into an output readable by the monitor. The controller 102 thentransmits the output to the monitor, and the monitor displays the dataoutput to a technician conducting the test. Therefore, the controller102 houses the electrical components not required proximal the electrodefor the electrode to function, (e.g., signal processing, power) at alocation other than the user's head, resulting in an EEG headset that iscomfortable to wear for an extended period. In one variation, thecontroller 102 is miniaturized, lightweight, and is arranged within oneof the bridge housings.

The systems and methods described herein can be embodied and/orimplemented at least in part as a machine configured to receive acomputer-readable medium storing computer-readable instructions. Theinstructions can be executed by computer-executable componentsintegrated with the application, applet, host, server, network, website,communication service, communication interface,hardware/firmware/software elements of a user computer or mobile device,wristband, smartphone, or any suitable combination thereof. Othersystems and methods of the embodiment can be embodied and/or implementedat least in part as a machine configured to receive a computer-readablemedium storing computer-readable instructions. The instructions can beexecuted by computer-executable components integrated bycomputer-executable components integrated with apparatuses and networksof the type described above. The computer-readable medium can be storedon any suitable computer readable media such as RAMs, ROMs, flashmemory, EEPROMs, optical devices (CD or DVD), hard drives, floppydrives, or any suitable device. The computer-executable component can bea processor but any suitable dedicated hardware device can(alternatively or additionally) execute the instructions.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the embodiments of the invention without departing fromthe scope of this invention as defined in the following claims.

We claim:
 1. A system for locating electrodes on a head of a usercomprising a headset comprising: a set of electrode bodies configured todetect electroencephalographic signals from the head of the user; and aset of spring elements: interconnecting and configured to elasticallylocate the set of electrode bodies on the head of the user; configuredto elastically deform to accommodate a size of the head of the user; andcomprising a first spring element: coupling a first electrode body ofthe set of electrode bodies to a second electrode body of the set ofelectrode bodies; characterized by a first spring rate; and comprising:first spine comprising:  a first spring segment; and  a second springsegment cooperating with the first spring segment to define a firstserpentine geometry comprising an even quantity of loops; a firstflexible circuit board comprising:  a first circuit board segmentarranged along a first side of the first spring segment; and  a secondcircuit board segment arranged along a second side of the second springsegment; and conductive transfer element:  electronically interposedbetween the first circuit board segment and the second circuit boardsegment;  extending over an edge of the first spine; and  extendingbetween the first side of the first spring segment and the second sideof the second spring segment; and a second spring element: coupling thefirst electrode body to the third electrode body; characterized by asecond spring rate less than the first spring rate; comprising:  asecond spine defining a second serpentine geometry comprising an oddquantity of loops; and  a second flexible circuit board arranged along afirst side of the second spring; and  cooperating with the first springelement to maintain relative positions of the first electrode body, thesecond to an electroencephalography standard.
 2. The system of claim 1:wherein the first spring element is configured to extend by a firstlinear amplitude; wherein the second spring element is configured to:extend by a second linear amplitude greater than the first linearamplitude; and cooperate with the first spring element to maintainrelative offsets between of the first electrode body, the secondelectrode body, and the third electrode body according to a 10-20electroencephalography standard.
 3. The system of claim 1: wherein thefirst spring element, in the set of spring elements, further comprises afirst insulative layer encasing a flexible circuit board of the firstspring element; and wherein the second spring element, in the set ofspring elements further comprises a second insulative layer encasing aflexible circuit board of the second spring element.
 4. The system ofclaim 1: wherein the first spring element cooperates with the secondspring element to constrain spacing of a set of electrode bodies torepeatably locate the set of electrode bodies at a target set ofpositions on a head of a user defined by the electroencephalographystandard.
 5. The system of claim 1: wherein the first spring element ischaracterized by a first cross-sectional area and the first spring rate;further comprising a third spring element: coupling the first electrodebody to a fourth electrode body in the set of electrode bodies;comprising a third spine defining the first serpentine geometry; andcharacterized by: a third cross-sectional area greater than the firstcross-sectional area of the first spring element; and a third springrate greater than the first spring rate.
 6. An electroencephalographyheadset comprising: a first electrode body; a second electrode body; athird electrode body; a first spring; coupling the first electrode bodyto the second electrode body; characterized by a first spring rate; andcomprising: a first spine comprising: a first spring segment; and asecond spring segment cooperating with the first spring segment todefine a first serpentine geometry comprising an even quantity of loops;a first flexible circuit board comprising: a first circuit board segmentarranged along a first side of the first spring segment; and a secondcircuit board segment arranged along a second side of the second springsegment; and a conductive transfer element: a second spring:electronically interposed between the first circuit board segment andthe second circuit board segment; extending over an edge of the firstspine; and extending between the first side of the first spring segmentand the second side of the second spring segment; and a second spring:coupling the first electrode body to the third electrode body;characterized by a second spring rate less than the first spring rate;comprising: a second spine defining a second serpentine geometrycomprising an odd quantity of loops; and a second flexible circuit boardarranged along a first side of the second spring; and cooperating withthe first spring to maintain relative positions of the first electrodebody, the second electrode body, and the third electrode body accordingto an electroencephalography standard.
 7. The electroencephalographyheadset of claim 6: wherein the first spine defines a U-shapedcross-section; and wherein the first flexible circuit board is arrangedwithin a channel of the U-shaped cross-section of the first spine. 8.The electroencephalography headset of claim 6: wherein the firstflexible circuit board is adhered along a first side of the first spine;and wherein the first flexible circuit board and the first spine iscoated with an insulative layer.
 9. The electroencephalography headsetof claim 6: wherein the first spring element is characterized by a firstcross-sectional area and the first spring rate; further comprising athird spring element: coupling the first electrode body to a fourthelectrode body in the set of electrode bodies; comprising a third spinedefining the first serpentine geometry; and characterized by: a thirdcross-sectional area greater than the first cross-sectional area of thefirst spring element; and a third spring rate greater than the firstspring rate.
 10. The electroencephalography headset of claim 6: whereinthe first spring element is configured to extend by a first linearamplitude; wherein the second spring element is configured to: extend bya second linear amplitude greater than the first linear amplitude; andcooperate with the first spring element to maintain relative offsetsbetween of the first electrode body, the second electrode body, and thethird electrode body according to a 10-20 electroencephalographystandard.
 11. The electroencephalography headset of claim 6: wherein thefirst spine comprises a first non-conductive injection-molded polymerforming a first flat spring with the first serpentine geometry; andwherein the second spine comprises a second non-conductiveinjection-molded polymer forming a second flat spring with the secondserpentine geometry.
 12. The electroencephalography headset of claim 6:wherein the first spring element comprises a first non-conductiveinjection-molded polymer characterized by a first elasticity; andfurther comprising a third spring element: coupling the first electrodebody to a fourth electrode body of the set of electrode bodies;comprising: a third spine defining the first serpentine geometry; and athird non-conductive injection-molded polymer characterized by a thirdelasticity different from the first elasticity of the firstnon-conductive injection-molded polymer of the first spring element; andcharacterized by a third spring rate different from the first springrate.
 13. The electroencephalography headset of claim 6: wherein thefirst electrode body: defines an electrode interface; and comprises anelectrical circuit electrically coupled to the electrode interface, thefirst spring element, and the second spring element; further comprisinga first electrode tip: configured to transiently locate onto andelectrically couple to the electrode interface of the first electrodebody; comprising: a conductive probe configured to electrically coupleto the head of the user; and an insulative boss configured to contactthe head of the user and transfer a weight of the electroencephalographyheadset to the head of the user.
 14. The electroencephalography headsetof claim 13: wherein the first electrode body further comprises anelectromagnetic shield: comprising a conductive injection-moldedpolymer; extending toward the conductive probe; and configured to shieldthe conductive probe from external electromagnetic radiation.
 15. Anelectroencephalography headset comprising: a first electrode body; asecond electrode body; a third electrode body; a first spring; couplingthe first electrode body to the second electrode body; characterized bya first spring rate; and comprising: a first spine comprising: a firstspring segment; and a second spring segment cooperating with the firstspring segment to define a first serpentine geometry comprising an evenquantity of loops; a first flexible circuit board comprising: a firstcircuit board segment arranged along a first side of the first springsegment; and a second circuit board segment arranged along a second sideof the second spring segment; and a conductive transfer element:electronically interposed between the first circuit board segment andthe second circuit board segment; extending over an edge of the firstspine; and extending between the first side of the first spring segmentand the second side of the second spring segment; and a second spring:coupling the first electrode body to the third electrode body;characterized by a second spring rate less than the first spring rate;comprising: a second spine defining a second serpentine geometrycomprising an odd quantity of loops; and a second flexible circuit boardarranged along a first side of the second spring; and cooperating withthe first spring to maintain relative positions of the first electrodebody and the second electrode body.
 16. The electroencephalographyheadset of claim 15: wherein the first spring element is characterizedby a first cross-sectional area and the first spring rate; furthercomprising a third spring element: coupling the first electrode body toa fourth electrode body in the set of electrode bodies; comprising athird spine defining the first serpentine geometry; and characterizedby: a third cross-sectional area greater than the first cross-sectionalarea of the first spring element; and a third spring rate greater thanthe first spring rate.
 17. The electroencephalography headset of claim15: wherein the first spring element comprises a first non-conductiveinjection-molded polymer characterized by a first elasticity; andfurther comprising a third spring element: coupling the first electrodebody to a fourth electrode body of the set of electrode bodies;comprising: a third spine defining the first serpentine geometry; and athird non-conductive injection-molded polymer characterized by a thirdelasticity different from the first elasticity of the firstnon-conductive injection-molded polymer of the first spring element; andcharacterized by a third spring rate different from the first springrate.
 18. The electroencephalography headset of claim 15: wherein thefirst spring element is configured to extend by a first linearamplitude; wherein the second spring element is configured to: extend bya second linear amplitude greater than the first linear amplitude; andcooperate with the first spring element to adjust the third electrodebody to a first position relative to a second position of the firstelectrode body.